Penetration simulation using ANSYS/explicit dynamic

- May 22, 2019 at 4:28 pm
  
  dal88236
  Subscriber
  
  Hi all,
  
  I am trying to do a simulation of a sharp needle penetrating the other material using ANSYS WB 19.2 explicit. The simulation is displacement controlled as the needle keeps going down in a certain rate and penetrates the material. According to the literature I found, the failure criterion should be von-mises stress criterion. As the equivalent stress in the element exceeds a specific value, the element will be deleted and the tip continue to go deeper.
  
  My question is that since the failure criteria I can choose in explicit seem not include VM stress criteria, how can I perform this simulation based on VM criteria. Or there is already a model can be chosen?
  
  Any help will be appreciated!
- April 19, 2020 at 1:22 pm
  
  Vahidebrahimi
  Subscriber
  
  Hi mate
  
  I introduced failure strain criterion that is between 10-25% to remove elements as penetrating. If you are not asked to use von Mises criterion, you can have a look at the principal failure strain of skin.
  
  I am also using explicit dynamics and want to measure the insertion force in time, do you know how I can measure insertion force - time. I am displacing the needle from the end to penetrate using Tabular displacement. In the available results, there is no Force components ! and I am trying to measure the force from the needle back (where the displacement is introduced).???
  
  Also, can you tell me what is your "End time" ? cause if I select my end time to be 3 sec. It will take ages to finish. So, I had to change it to smaller value of end times 1e-3. This end time is not realistic as my real end time based on needle movement should be 3 sec. Do you have any idea for my case???
  
  Kind Regards